Hydraulic check



March 7, 1944. H. A. KNox HYDRAULIC CHECK` Original Filed Jan. 6, 1942 3 Sheets-Sheet l Hurry' A Knmx March 7, 1944. H. A. KNOX HYDRAULIC CHECK Original Filed Jan. 6, 1942 3 Sheets-Sheet 2 if IA'I/ me/whoa Hurry A Knmx az, w. MM

March 7, 1944. H. A. KNOX u HYDRAULIC CHECK original Filed Jan. 6. 1942 5 Sheets-Sheet 5 Huby A KTLDX @JJMLM Patented Mar. 7, 1944 Harry A. Knox, Washington, D. C.

Original application January 6, 1942, Serial No.

425,717. Divided and this application September 7, 1942, Serial No. L157,596

.1 Claim.

k(Granted under the act of March 3, 1883, as amended April 30, 1928; 37 0 O. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This is a division ofy my copending application Serial No. 425,717, filed January 6, 1942.

This invention relates to a suspension for vehicle wheels having means for checking abnormal movement of the wheels.

An object of this invention is to provide a resilient wheel suspension incorporating a hydraulic check.

Another object of this invention is to provide a resilient Supporting means for wheels of a vehicle incorporatingtherein appara-tus for causing the wheels to have a greater resistance to movement in one direction than in the other.

Another object of this invention is to provide hydraulic means for controlling the movement of the wheels of a track laying vehicle.

Another object of this invention is to provide a wheel suspension for track laying vehicles in which spring means are combined with hydraulic means so as to absorb large amounts of road shock with a relatively small amount of discomfort to the occupants.

Another object of this invention is to provide an improved fluidtight connection between a fluid cylinder and a piston rod.

Another object of this invention is to provide an improved check valve mounted in a piston of a nuid cylinder.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. l is a sectional view taken substantially on line I-I of Fig. 2.

Fig. 2 is a plan viewA of the suspension and hydraulic checky and a portion of the supporting means in section.

Fig. 3 is a view taken substantially on line 3 3 of Fig. 1.

Fig. 4 is a view taken substantially on line '4-4 of Fig. 1.

Fig. 5 is a View taken substantially on line 5-5 of Fig. 1.

Fig. 6 is a plan View of one of the wheel supporting arms detached froml the hydraulic check; a portion of the clamping means for contact shaft e is shown in section.

Fig.- 7 a View takensubstantially on line I-.l or Fis. 1-

Referring to the drawings wherein like numerals designate like parts, the suspension is adapted to be rigidly xed to a portion I0 of the vehicle frame and to carry a pair of wheels II resiliently.

The suspension proper is supported by two brackets I2, I3 which also serve to house the Imovable portions of the suspension. The brackets I 2 ,I3 are rigidly interconnected by means of two shafts I 4, I 5 which have their ends rigidly fastened in split hollow portions I2a, I3a. (Fig. 3) in the brackets I2, I3 respectively by means of clamping bolts I6 which pass through shaft grooves Ma, Ita. The split hollow bracket portions I2a, ISa are drawn up tight around the shafts I,r I5 by means of nuts Ilia respectively; also, shaft grooves Ita., I5a cooperate with the body portion of bolts I6 so as to prevent rotation and axial movement of shafts Ill, I5. The movable portions of the suspension are adapted to oscillate about the fixed shafts I4, I5.

The movable portion of the suspension may be considered to have four arms I1, I8, I9, 20 which are in pairs Il, I8, and i9, 20 so as to be disposed on opposite ends of the volute springs S, S. Arm I'I is permanently joined to and spaced from arm I 8 by means of a welded connection between those arms and tubular member 2 I; similarly arm I9 is permanently joined to and spaced from arm 20 by means of a welded connection between those arms and tubular member 22. Tubular members 2I, 22 are adapted to receive shafts I5, I4 respectively and to be disposed between bracket abutments I2h, I 3b. Elastic material 23, 24 such as rubber is' disposed between shafts I4, I5 and tubular members 2|, 22 in such a fashion, well understood in the art, that relative movement between the shafts and tubular members is accommodated by the resiliency of the material 23, 24 respectively.

Each of the arms I'I, I8, I9, 2D are of similar construction and have members similar to those of I'Ia, I'Ib, Ilc, Ild, Ile on arm il; those members are lettered similarly to those of arm I1 in the drawings. Those members serve to join hollowportions similar to those of I'ig, I'Ih, lli and II in arm Il in aligned relationship so that a shaft passing through one of the arm hollow portions will also pass ,through a corresponding hollow portion in the other arm which forms a pair with the last mentioned arm.

A pair of volute 'springs'.S, S have their ends abuttingagainst spring seats 25, 26 whichhave outside hannelportions 25a., 26a adapted to receive nat contact barsr25b, 26h and cylindrical shafts `25e, 26e re,spe ctively. A linecontact is thus provided between the last mentioned shafts and their contact bars and in case this line contact is impaired by wear or other causes a new one may be established by loosening clamping screws 25d, 26d which clamp split hollow arm portions lli, |81', |91, 20i to the ends of shafts 25C, 26e respectively and then rotating the shafts a small amount; the split hollow portions are then reclamped to the ends of their shafts by screwing clamping screws 25d, 26d in tapped holes 25g, 26g. Tapped hole 25g is shown in section in Fig. 6l and of course tapped hole 26g is of similar structure.

Projections 26e (Fig. l)l on the spring seats 26 project into the hollow -of the volute springs and together with flanges 25e (Fig. 3) on springV seat 2'5 maintain the volute springs S, S ,in position. Tapped holes 261 (Fig. 1) in spring seat 26 are made of avail in'assembling the suspension. An assembly rod (not shown) is adapted to pass through hole 251 in spring seat 25 and to screw in one of the tapped holes 261 in spring seat 26.

Features of the resilient suspension thus far described are disclosed in my copending application iiled on the same date as the application of which this instant application is a division and also in my copending application, Serial No. 399,661, iiled June 25, 1941. This instant application relates more particularly to the features of the hydraulic check in combination with the resilient suspension thus far described.

The hydraulic check assembly having hardened bushings 29, 29' integral therewith is centrally and rotatably mounted on shafts 2l, 28 which are held fast in the arm hollow portions I'ly', IS7 and |97', 209' by means of Cotter pins I'Uc, |81: and I 9k, 20k, respectively. The hydraulic check has three major parts, i. e., piston 32, the head or closure 30 and cylinder 3|, and those latter two parts are clamped together by means of four circumferentially disposed bolts passing through four ears 3|p on the cylinder 3| and engaging tapped portions in the head. A resilient oil resistant gasket may be interposed between those two major portions 30, 3| so as to provide a resilient connection therebetween. The head has a hollow portion 30a having the hardened bushing 29 fastened therein so asto provide a good wearing surface .between shaft 21 and the head 30.

Piston 32 having a pair of ball check valves 3l, 38 or similar closure members mounted therein is adapted to move with respect to its cylinder 3| when there is relative movement between the pairv of arms I1, I8 and pair of arms I9, 2|) since the cylinder 3| is rotatably mounted on arms I1, I8 and the piston rod is rotatably mounted on arms I9, 20 by means of a pin connection 33a between piston rod 33 and the hollow portion 35a of rotatable sleeve 35. A hardened bushing 29' fastened in sleeve 35 is adapted to rotate on hardened shaft 28. y

Piston 32 has two types yof fluid ports therein, i. e., a port 36 having a` constant opening and ports of the type adapted to be open only when theA wheels of the vehicle are quickly raised relative to one another. Two ball check valves 31, 3B are used in this particular embodiment of my invention arrangement disclosed, or .more than two balli check valves may be disposed in the piston. It

is desirable to use a plurality of small ball check 7 valves instead of one large one for smooth operation for then the composite check valve structure has a smaller opening for a given displacement of the wheels.

The cylinder is lled with oil through an opening 54 in the cylinder headupl to -the level of the other opening 54' and it is seen that due to the shape of head 30 an air reservoir B is provided in the head when the opening 54 and overow opening 54' are closed after the filling operation. Openings 54 and 54' are closed by means of ythe threaded bolts shown in Fig. 5. In operation of the piston, the oil from the left side of the piston (oil chamber) (Fig. 1) may either flow through control hole 36 via opening 36a or check valves 31, 38 to the right of the piston (compression chamber C) and, if oil leakage occurs between rod 33 and the snug tting cylinder hole 39, the oil which leaks through 39 accumulates in cylinder hollow portion 40 from where itis returned to the left hand side of the piston through oil return port or conduit 4| (Fig. 7). The air reservoir B provided in. the cylinder head serves as a cushion and an expansion chamber for the oil in the oil chamber A and the pressure developed therein upon movement of the piston to the left (Fig. 1)H together with the stored energy in volutesprings S, S' serve to return the piston 32 to the right;

however, piston 32 moves to the right more slowly than when it moved to the left because bali` check valves 3l, 38 prevent the flow of oil to the oil chamber from the compression chamber C to the oil chamber A. The-flow of oil from the compression chamber C to the koil chamber 35 A occurs through control hole 3,6 via opening 36a but for any small undesired leakage through 3,9 and the ball check valves 31, 38. It is fundamental to realize that opening 36 may be made variable although the drawings show opening 36 40 to have a xed opening.

An oiltight; joint is provided between the cylinder 3| and piston rod 33 at the place of emergence of the piston rod from the cylinder. This joint may be constructed in a mannerwell known in the art and the one shown herein comprises two oil retainer rings 46, 41' in the cylinder recess 3| a. The retainer rings fill up the space between the cylinder and piston shaft 33 and are held in the cylinder recess by `means of a ring 48. y "j It is noted that the pressure onjthe oiltight joint 45 never reaches thepressure inthe compression chamber C because of the snug fit vbel tween piston rod 33and cylinder hole 39, and the oil return port 4| (Fig. 7); accordingly4 an elaborate high pressure oiltight joint 45 is not necessary in order that therebe nooil leakage from the oil cylinder to the outsidal Balls 5|), 5| of check valves 3l, 38 tinto rounded seats 52, 53 on the piston 33 so that passage of oil from compression chamber C to oil chamber A through ports 32a, 32h isprvented. The balls 50, 5| may move radially-with lrespect to the cylinder 3| in the radialpiston the inner surface of cylinder 3|. .Inorderto-remove the balls from the openings 32o it is necessary to separate-the cylinder closure .or'head 30 from the cylinder 3| and move the. piston 32 out of its cylinder 3| whereby `the innersurface .of

the cylinder 3| no longerjres'trainsvthehballs.` f.: `Suitable holes .|2e, |3e are providedjin b`rack" ets I2, I3 for fastening the brackets to ai portion 'of the vehicle by means of bolts,or other sir'nilar means.

openings 32c and have their motion limited by It is seen that a suspension and hydraulic check for two wheels of the vehicle are disclosed in the drawings in which the wheels have a common shock absorbing means; but, for purposes of analysis of one phase of applicants invention, it is also seen that each wheel axle has an independent action even though the other Wheel is held rigidly and considered t0 be a portion of the vehicle bracket.

Also, the wheel axles disclosed may rotate with the wheels or they may be held fast in their supporting frames.

The check valves 31, 38 are shown in the drawings as providing a check for the rapid return of the volute spring S, S from a compressed position to a lesser compressed position. It is understood that the orifice 36 and the cylinder oil chamber B may be designed so that the time necessary for the spring to return to its less compressed position may be varied, i. e., orice 36 may partake of an adjustable valve.

I claim:

In a machine having wheels mounted on axles and having a frame, means for pivotally mounting two wheel axles on the frame with their axes parallel, a spring between the two wheel axles and having two opposite ends movable with respeci; to one another, rigid means extending from one axle to one of said opposite ends and rigid means extending from the other axle to the other opposite end, a uid cylinder, a piston in the fluid cylinder, a rigid arm extending from one axle to the cylinder and having pivotal connection with said cylinder, and rigid means extending from the other axle to the piston having pivotal connection with said piston.

HARRY A. KNOX. 

